Ah, crazy! Makes sense though, that stuff is real gooey. I didn't notice that in my filter on my 750 when I rebuilt the engine in October, but I wasn't exactly looking for it either...
I put in some Rotella T 15w-40 oil in, which is my normal choice. It's cheap and works well in these engines in my experience. I think I won't start the bike up again till the snow clears and I can actually ride it. I'd rather not have the engine sit idling so much, but rather take it on a short (maybe 20-30km), fast ride to start the break in and circulate the oil a bit, change the oil right after, then again at 100km.
Next project on the list is addressing the leaking petcock and fuel cap. I'll see about addressing that this weekend.